Type IV Hypersensitivity: Delayed

Type IV hypersensitivity

Delayed hypersensitivity

Protein (insect venom, mycobacterial proteins)

What type of antigen causes delayed-type hypersensitivity?

Local skin swelling (erythema, induration, cellular infiltrate, dermatitis)

What is the result of delayed-type hypersensitivity?

Haptens and small metal ions (nickel and chromate)

What type of antigen causes contact hypersensitivity?

Local epidermal reaction (erythema, cellular infiltrate, vesicles, and intraepidermal abscesses)

What is the result of contact hypersensitivity?

Th1 effector cells

In delayed type hypersensitivity, after an antigen is injected into subcutaneous tissue, what cell recognizes the antigen and releases cytokines?

Langerhans cells and Th1 cells

Contact hypersensitivity occurs through what two cells?

Kertainocytes

Aside from Th1 cells, what other kind of cells secrete cytokines in response to contact hypersensitivity?

Cell mediated immunity

Antigens that stimulate ________ will cause the development of Type IV hypersensitivity

1. Survive inside macrophages/difficult to digest and eliminate

2. Haptens that bind to skin proteins

What kind of antigens lead to type IV hypersensitivity?

A

T or F: Lesions for type IV hypersensitivity occur at point of contact with antigen

1. Allergic contact dermatitis (contact hypersensitivity)

2. Intradermal diagnostic tests for antigens that trigger CMI

3. Cutaneous basophil hypersensitivity

What are the three clinical forms of type IV reactions?

Langerhans cells

What is the principal antigen presenting cell for contact hypersensitivity?

Sensitization and elicitation

What are the two stages of contact hypersensitivity?

Ventral abdomen

Where is allergic contact dermatitis typically located at on dogs?

B (spiderwort can though)

T or F: Poison ivy commonly causes contact dermatitis in dogs

Steroids

What is the treatment option for allergic contact dermatitis?

Eosinophils

Granulomatous inflammation has no _____________

Cutaneous basophil hypersensitivity

Occurs when effect CD4+ T cells release cytokines that attract and activate basophils

Fleas, ticks, and Culicoides spp.

What commonly causes cutaneous basophil hypersensitivity?